A radiofrequency source used in an antenna consists of a radiating element coupled to an RF radiofrequency chain. In low-frequency bands, for example in the C band, the radiating element often consists of a horn and the RF chain includes RF components intended to perform dual-polarization or single-polarization reception and emission functions in order to meet the needs of users. Links with ground stations are generally dual-polarization.
The mass and bulk of RF radiofrequency chains is a critical point in the field of space antennae intended to be installed onboard satellites, in particular in the domain of the lowest frequencies such as in the C band. In the high-frequency domain, for example the Ka band or Ku band, there exist very compact radiating elements the technology of which may be transposed to the C band, but the radiofrequency sources obtained remain bulky and of substantial mass and installation problems arise when they must be integrated into a focal array including many sources.
Cavity-backed radiating elements that have the advantage of being compact exist, but these radiating elements are limited in terms of passband and can be used only in single-polarization and in a single operating frequency band or in two very narrow frequency bands.